The colon is a part of the intestine, extending from the small intestine to the rectum. The colon is primarily responsible for extracting water from digestive waste. The colon is a flexible organ, and undergoes deformations and forms changes with time. Such deformations may include, for example, stretching, contracting, twisting, and the like. Colon cancer is a major cause of death throughout the world. Early detection of malignant tumors, which manifest themselves initially as polyps or cysts in the colon, can greatly improve the chances of recovery of a diagnosed patient.
Stereoscopic imaging of the colon (i.e., stereoscopic colonoscopy) presents a challenge due to the flexible and constantly-changing nature of the colon. Deformations of the colon make it difficult to retrace particular areas of the colon, at different times. If a physician identifies an abnormal feature in a colon of a patient (e.g., a polyp), then the physician may wish to further examine that abnormal feature at a later time, in order to follow its development. However, it may be difficult for the physician to locate the same feature of the colon, due to the deformation undergone by the colon. Stereoscopic image detection devices, used in colonoscopy, are known in the art. Known colonoscopy devices also employ systems and methods for determining the spatial position of the medical device relative to a known reference system.
U.S. Pat. No. 6,167,296 issued to Shahidi, and entitled “Method for Volumetric Image Navigation”, is directed to a navigation system for a surgical procedure. The navigation system includes a set of fiducial markers, a surgical probe, a computer, a display device, a sensing unit, and a set of two light emitting diodes (LEDs).
The fiducial markers are attached to a head of a patient. The computer is connected with the display device, the sensing unit and with the surgical probe. The LEDs are connected with the surgical probe. The sensing unit is mounted above an operating table, on which the surgical procedure takes place.
The locations of the fiducial markers are the same as their locations at a previous time of acquiring a three-dimensional image of the head of the patient. The three-dimensional image of the head is acquired previously, by Magnetic Resonance Imaging (MRI). The computer stores the MRI image of the head, in a memory thereof. The computer generates a three-dimensional model from the MRI image. The fiducial markers allow alignment of the position and orientation of the head, such that it is the same at the time of the surgical procedure, as it was when the MRI image was acquired.
A surgeon directs the surgical probe toward a tissue of interest in the head of the patient. The LEDs emit infrared pluses. The sensing unit senses the infrared pulses. The computer controls the timing and synchronization of the infrared pulses, and the recording and processing of the infrared pulses received by the sensing unit. The computer processes the infrared pulses to generate data indicating the location and orientation of the surgical probe in real time, and records this data. The computer displays on the display device, a three-dimensional image of the head of the patient, respective of the position and orientation of the surgical probe.
U.S. Pat. No. 6,226,543 issued to Gilboa et al., and entitled “System and Method of Recording and Displaying in Context of an Image a Location of at Least One Point-Of-Interest in a Body During an Intra-Body Medical Procedure”, is directed to a system for simultaneously obtaining location data of a body of a patient, location data of a catheter inserted into the body, and location data of an imaging instrument. The system is used for imaging the catheter and the body, and recording that data. The system includes an imaging instrument, a catheter, a locating implement, a location implement, a computer, and a monitor.
The computer is connected with the monitor, the imaging instrument and with the locating implement. The location implement is a transmitter which emits electromagnetic waves, positioned at the tip of the catheter. The locating implement is a receiver which receives electromagnetic waves, located above the operation table, within an effective distance with respect to the location implement. The body is fixed at a known location during the procedure (i.e., on the operating table). The imaging instrument is located above the operation table.
A surgeon inserts the catheter into a portion of the body of the patient. The surgeon employs the imaging instrument for imaging of that portion of the body. The surgeon advances the tip of the catheter to a point-of-interest in that portion of the body. The locating implement locates the location implement, and the computer records the location of that point. The point-of-interest is projected and displayed on the monitor, in relation with the respective location of the body and with the respective location of the imaging instrument. Thus, the surgeon can locate the point-of-interest, recorded at a previous time, when the imaging instrument was positioned differently relative to the operating table.
U.S. Pat. No. 5,902,239 issued to Buurman, and entitled “Image Guided Surgery System Including a Unit for Transforming Patient Positions to Image Positions”, is directed to a system for guided surgery using a camera and a plurality of LEDs. The system includes two cameras, a plurality of LEDs, a computer, a surgical instrument, a plurality of fiducial markers and a monitor.
The computer is connected with the monitor and with the cameras. The LEDs are positioned on the surgical instrument. The locations of the fiducial markers are substantially the same as their locations at a previous time of acquiring a Computed Tomography (CT) image of the patient. The computer contains the CT image. The cameras are sensitive to the light emitted by the LEDs. The computer receives image signals from the cameras. The computer computes the position of the surgical instrument relative to a body of the patient, according to the image signals acquired by the cameras. A surgeon indicates the location of the fiducial markers, by pointing at the fiducial markers with the surgical instrument. The computer computes the corresponding position of the fiducial markers in the CT image, and in the current images acquired by the cameras. The computer computes a transformation matrix for transforming each point in a reference coordinate system of the current images, to a reference coordinate system of the CT image. The computer computes the corresponding position of the surgical instrument in the CT image reference coordinate system. The computer displays, on the monitor, a superimposed image of the surgical instrument in the CT image.
U.S. Pat. No. 6,923,768 issued to Camus et al., and entitled “Method and Apparatus for Acquiring and Displaying a Medical Instrument Introduced into a Cavity Organ of a Patient to be Examined or Treated”, is directed to a system for recognizing the position of a treatment or examination device. The system includes a treatment apparatus, a control and processing device (CPD), an ultrasound acquisition device, a plurality of position sensors, a position acquisition system, a medical instrument and a monitor.
The CPD is connected with the ultrasound acquisition device, the position acquisition system and with the monitor. One of the position sensors is integrated into the ultrasound acquisition device and another position sensor is integrated into the medical instrument.
A physician displaces and turns the ultrasound acquisition device in a cavity organ of a patient, in order for the ultrasound acquisition device to acquire two-dimensional (2D) ultrasound images of the interior of the cavity organ. The position acquisition system acquires the spatial position and orientation of the ultrasound acquisition device, in the coordinate system of the position acquisition system. The CPD generates a three-dimensional (3D) ultrasound image dataset on the basis of the 2D ultrasound images. The CPD generates a 3D reconstruction image, according to the 3D ultrasound image dataset. The resolution of the 3D ultrasound image dataset grows as the number of acquired 2D ultrasound images grows. The position acquisition system acquires the position of the medical instrument in a coordinate system of the position acquisition system. The CPD displays on the monitor, the 3D reconstruction image and the respective position of the medical instrument.